JPH0914059A - Evaporation fuel discharge restraining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaporation fuel discharge restraining device for smoothly performing supply of oil in a fuel tank in emergency that a control valve fails. SOLUTION: A fuel tank 10 and outside air are communicated with each other by an evaporation fuel discharging pipe 40 provided in parallel with a filler pipe 30 for supplying fuel to the fuel tank 40, and an evaporation fuel cap 41 is attachably and detachably provided on an evaporation fuel discharging port 40a of the evaporation fuel discharging pipe 40. When a control valve 73 interposed in a charge passage 71 of an evaporation discharge restraining device fails, the evaporation fuel discharging pipe 40 is made to function as an emergency line by removing the evaporation fuel cap 41, and the evaporation fuel in the fuel tank 10 can be quickly discharged to the outside air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative emission control device for use in a fuel system of an internal combustion engine such as an automobile engine and for inhibiting evaporative fuel generated from a fuel tank from being discharged to the outside air.

[0002]

2. Description of the Related Art Conventionally, in a fuel system of an internal combustion engine, in order to avoid the problem that evaporated fuel generated inside a fuel tank is temporarily collected by a canister or the like and the evaporated fuel is discharged to the outside air, Equipped with various evaporative emission control devices.

FIG. 3 shows a conventional vaporized fuel emission suppressing device of the charcoal canister type, which is a canister 60 containing a fuel tank 10 and an adsorbent for the vaporized fuel.
Are connected to a first charge passage 71 and a second charge passage 74 on the fuel tank 10 side by a bifurcated charge passage 70. In order to reduce the internal pressure of the fuel tank 10 during refueling, a control valve 73 is provided in the first charge passage 71 downstream of the first float valve 72,
A two-way valve 76 is provided in the second charge passage 74 downstream of the second float valve 75 in order to keep the evaporated fuel inside the fuel tank 10 at a specified pressure when the internal combustion engine is operating and when it is stopped. .

On the other hand, the fuel tank 10 and the cap storage unit 20 are connected by a filler pipe 30, and a fuel cap 31 is detachably attached to an oil supply port 30a of the filler pipe 30. A filler lid 21 is hinged to the cap storage unit 20 so as to be openable and closable so that the internal space of the cap storage unit 20 can be shielded from the outside air.

According to such a conventional device, when the internal pressure of the fuel tank 10 exceeds a specified level during operation and stop of the internal combustion engine, the evaporated fuel passes through the second float valve 75 and the two-way valve 76, It is delivered from the second charge passage 74 to the canister 60 via the charge passage 70. In this way, the internal pressure of the fuel tank 10 is maintained at a specified level, but this specified pressure is usually not equal to atmospheric pressure.

Therefore, when the fuel tank 10 is refueled, the control valve 73 is opened so that the evaporated fuel in the fuel tank 10 is sent from the first charge passage 71 to the canister 60 via the charge passage 70, and the fuel tank 10 is refueled. The inside of 10 is decompressed. Then, in particular, in order to detect the start of refueling of the fuel tank 10 and control the opening / closing of the control valve 73, the opening / closing of the filler lid 21 constituting the cap storing unit 20 is detected, and the attachment / detachment of the fuel cap 31 is detected, Alternatively, the insertion / removal of the fuel injection gun is detected.

Incidentally, such a prior art is disclosed in Japanese Unexamined Patent Publication No.
It is disclosed in detail in Japanese Patent No. 10215.

[0008]

However, in the above-mentioned conventional vaporized fuel discharge restraint device, when some trouble occurs and the control valve does not open at the time of refueling, the internal pressure of the fuel tank remains high. Become. For this reason, it becomes difficult to insert a fuel injection gun (not shown) into the filler pipe 30 from the fuel supply port to inject the fuel into the fuel tank 10, and there is a possibility that the fuel cannot be suitably refueled.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an evaporative emission control device capable of smoothly refueling a fuel tank in an emergency when a control valve fails. And

[0010]

According to a first aspect of the present invention, a canister connected to a charge passage connected to a fuel tank and adsorbing and releasing evaporated fuel generated in the fuel tank is installed in the middle of the charge passage. And a control valve that opens the charge passage when refueling the fuel tank, and supplies the fuel to the fuel tank in the evaporated fuel discharge suppression device that supplies the evaporated fuel to the engine through the purge passage connected to the canister. It is characterized in that it is provided with an evaporative fuel discharge pipe connected to the upper part of the fuel tank, which is attached to the filler pipe, and is connected to the outside air through the evaporative fuel discharge port, and an evaporated fuel cap for opening and closing the evaporated fuel discharge port. .

In the evaporative emission control device of the present invention,
When the internal combustion engine is in a normal operating state or in a stopped state, the fuel filler port is closed by the fuel cap, and the evaporated fuel discharge port is closed by the evaporated fuel cap. Therefore, the evaporated fuel generated from the fuel is held inside the fuel tank, the purge passage, and the canister.

On the other hand, when fuel is supplied to the fuel tank, the control valve opens the charge passage, so that the evaporated fuel in the fuel tank flows into the charge passage and is temporarily stored in the canister. The internal pressure of the fuel tank almost opposes the atmospheric pressure.

At this time, even if some trouble occurs and the control valve does not operate, the operator removes the vaporized fuel cap from the vaporized fuel discharge port, so that the vaporized fuel inside the fuel tank releases the vaporized fuel. Is released into the atmosphere via. Therefore, the internal pressure of the fuel tank almost opposes the atmospheric pressure, so that the fuel can be easily injected into the fuel tank from the fuel injection gun.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The configuration and operation of an embodiment of an evaporated fuel discharge restraint system of the present invention will be described in detail below with reference to FIGS. 1 and 2.

First Embodiment As shown in FIG. 1, the evaporative emission control device of this embodiment is a system in which a fuel tank 10 for storing a fuel 11 is arranged at the center. A filler pipe 30 through which a fuel injection gun (not shown) is inserted is connected to the fuel tank 10 and has a lower end protruding into the internal space of the fuel tank 10, and a fuel cap 31 is detachably attached to a fuel filler port 30 a at the upper end of the filler pipe 30. Has been. Further, the lower end of the evaporated fuel discharge pipe 40 arranged in parallel with the filler pipe 30 is connected to the upper part of the fuel tank 10, and the opening of the upper end thereof forms the evaporated fuel discharge port 40a for discharging the evaporated fuel to the outside air. An evaporated fuel cap 41 is removably installed on the evaporated fuel discharge port 40a.

Here, the cap storage unit 20 for storing both the fuel cap 31 and the evaporated fuel cap 41 in the internal space is recessed inside the body covering the fuel tank 10 and has the fuel supply port 30a and the evaporated fuel discharge port 40a at the bottom. And a cap storage part 21 that is rotatably supported (hinge connection) on the body.
And a substantially flat filler lid 22 that opens and closes.

The evaporative fuel discharge pipe 40 characteristic of the present embodiment is a substantially cylindrical pipe for sending the evaporative fuel generated from the fuel 11 inside the fuel tank 10 to the outside from the evaporative fuel discharge port 40a. The fuel cap 41 is an airtight sealing cap that opens and closes the evaporated fuel discharge port 40a.
Therefore, the evaporated fuel discharge pipe 40 functions as an emergency line that reduces the internal pressure of the fuel tank 10 by removing the evaporated fuel cap 41 in an emergency when the control valve 73 does not operate.

Fuel tank 10 through charge passage 70
The canister 60 connected to is a mechanism that temporarily stores (adsorbs) the evaporated fuel that has flowed from the fuel tank 10 through the charge passage 70 and then releases (releases) it, and supplies it to the internal combustion engine. It is divided into two chambers that are partially communicated with each other by a partition 61, and is filled with an adsorbent 62 made of activated carbon. One chamber of the canister 60 is communicated with the fuel tank 10 by the charge passage 70, is communicated with the combustion chamber of the internal combustion engine by the purge pipe 90, and the other chamber is communicated with the outside by the drain pipe 80. The drain pipe 80 discharges the charge gas from which the evaporated fuel is removed by the canister 60 to the outside, and sucks the outside air into the canister 60 by the suction negative pressure of the purge pipe 90.
Further, the purge pipe 90 delivers the evaporated fuel released from the canister 60 to the combustion chamber of the internal combustion engine.

The charge passage 70 connected to the canister 60 includes a first charge passage 71 and a second charge passage 74.
Is connected to the fuel tank 10 in two branches, the first charge passage 71 is sequentially through the float valve 72 and the control valve 73, and the second charge passage 74 is the check valve 75 and the two-way valve 7.
The vaporized fuel is made to flow in through 6 in sequence.

The control valve 73 interposed in the first charge passage 71 is based on the operation of a switch (not shown) for detecting the opening or closing of the filler pipe 30, and an electronic control unit (ECU) not shown. ), The first charge passage 7 is electrically controlled to open and close when the fuel cap 31 closes the filler pipe 30.
1 is closed, and the first charge passage 71 is opened when the fuel cap 31 is removed during refueling. On the other hand, the two-way valve 76 interposed in the second charge passage 74 is a valve that adjusts the internal pressure of the second charge passage 74 with a negative pressure valve and a positive pressure valve, and the pressure on the upstream side of the second charge passage 74 is the downstream side. When the pressure on the upstream side of the second charge passage 74 is higher than the atmospheric pressure, the negative pressure valve opens to open the second charge passage 74 when the pressure is lower than the side pressure. Open the passage 74, the second when not in these conditions
The charge passage 74 is closed.

The first float valve 72 is a valve that opens and closes the first charge passage 71 in response to lifting and lowering of the float. When the liquid level of the fuel 11 in the fuel tank 10 rises by a normal refueling operation, the first float valve 72 The charge passage 71 is closed to prevent the fuel 11 from leaking from the fuel tank 10. The second float valve 75 is a cut-off valve that opens and closes the second charge passage 74 in response to lifting and lowering of the float. When the liquid level of the fuel 11 changes in the fuel tank 10 due to the inclination of the body itself, the second float valve 75 The charge passage 74 is closed to prevent the fuel 11 from leaking out.

Next, the operation of the present embodiment will be described.

When the internal combustion engine is in a normal operating state or in a stopped state, the fuel cap 31 closes the fuel supply port 30a of the filler pipe 30, and the evaporated fuel cap 41 closes the evaporated fuel discharge port 40a of the evaporated fuel discharge pipe 40. doing. The control valve 73 closes the first charge passage 71 because the filler pipe 30 is closed.

At this time, when the internal pressure of the fuel tank 10 is less than the predetermined level, the two-way valve 76 closes the second charge passage 74. On the other hand, when the internal pressure of the fuel tank 10 exceeds a predetermined level due to the evaporated fuel, the two-way valve 76
Opens the second charge passage 74.

In the latter case, the evaporated fuel held inside the fuel tank 10 flows into the charge passage 70 from the second charge passage 74 and is delivered to the canister 60.
Therefore, the internal pressure of the fuel tank 10 is maintained below a predetermined level. On the other hand, the evaporated fuel flowing into the canister 60 is adsorbed by the adsorbent 62 filled in the canister 60, then separated from the adsorbent 62 by the atmosphere guided to the canister 60 via the drain pipe 80, and the purge pipe 90
Is guided to the internal combustion engine via the and is burned.

When the fuel 11 is supplied to the fuel tank 10 (at the time of refueling) with the internal combustion engine stopped, the operator opens the filler lid 22 of the cap storing unit 20 and then from the filler port of the filler pipe 30. Fuel cap 31
Remove. Then, the open state of the filler pipe 30 is detected by a switch or the like, and the control valve 73 opens the first charge passage 71.

At this time, if the internal pressure of the fuel tank 10 exceeds the atmospheric pressure, the evaporated fuel in the fuel tank 10 flows into the charge passage 70 from the second charge passage 74 and is delivered to the canister 60. Therefore, the internal pressure of the fuel tank 10 is maintained at about atmospheric pressure, and no particular trouble occurs in refueling work.

In this case, the control valve 73 is damaged due to some failure.
If the fuel tank 10 does not operate, the operator removes the evaporated fuel cap 41 from the evaporated fuel discharge port 40a of the evaporated fuel discharge pipe 40, and the fuel tank 10 is removed from the evaporated fuel discharge pipe 40.
Is communicated with outside air via. Therefore, the fuel tank 10
The evaporated fuel held inside the
0 and released through the cap storage unit 20 to the outside air. Therefore, since the internal pressure of the fuel tank 10 almost opposes the atmospheric pressure, the operator inserts the fuel injection gun into the filler port 30a of the filler pipe 30,
Fuel 11 is supplied to the fuel tank 10 through the filler pipe 30.
Can be easily injected.

Further, even if the float valve 72 fails or the pressure drop due to dust in the canister 60 occurs, the evaporated fuel cap 41 is similarly removed, and the fuel is discharged through the evaporated fuel discharge pipe 40 functioning as an emergency line. The internal pressure of the tank 10 can be reduced.

Second Embodiment FIG. 2 is a sectional view showing a second embodiment of the evaporated fuel discharge restraining apparatus. This evaporated fuel discharge restraining apparatus 2 is the evaporated fuel discharge restraining apparatus of the first embodiment described above. 1 is substantially the same as that of the first embodiment, except that an evaporative fuel return pipe 50 is installed so as to connect the filler pipe 30 and the evaporative fuel discharge pipe 40 to each other.
The difference is that the one-way valve 51 is installed in the middle of the evaporated fuel return pipe 50. The difference will be described below.

The vaporized fuel return pipe 50 is a substantially cylindrical pipe for sending the vaporized fuel generated inside the fuel tank 10 from the vaporized fuel discharge pipe 40 to the filler pipe 30. By using this evaporated fuel return pipe 50, when the fuel 11 is supplied to the fuel tank 10, it is possible to reduce the entrained air flowing into the fuel tank 10 from the filler pipe 30, and at the same time, in the fuel tank 11. Generation of evaporated fuel can be suppressed.

The one-way valve 51 is a valve that opens and closes the vaporized fuel return pipe 50 according to the difference between the internal pressure of the vaporized fuel discharge pipe 40 and the internal pressure of the filler pipe 30. Therefore, by using the one-way valve 51, when the internal pressure of the evaporated fuel discharge pipe 40 is higher than the internal pressure of the filler pipe 30 by a predetermined level or more, the evaporated fuel return pipe 50 is opened and the evaporated fuel is returned to the filler pipe. You can return to 30.

The present invention is not limited to the above-described embodiment, but various modifications can be made.

For example, in the above-described embodiments,
The control valve 73 of the first charge passage 71 is electrically opened / closed based on an output signal of a switch that detects opening or closing of the filler opening 30a of the filler pipe 30. However, the control valve 73 may be mechanically opened and closed based on the operation of a switch that detects the opening and closing of the filler pipe 30.

An EC for electrically controlling the control valve 73
U may control an electronically controlled fuel injection system that adapts the injection of fuel corresponding to the electrically detected intake air amount to the operating conditions of the internal combustion engine.

[0036]

As described in detail above, in the evaporative emission control device of the present invention, the evaporative fuel discharge pipe is arranged in parallel with the filler pipe, and the fuel tank and the outside air are communicated with each other to evaporate. Since the fuel cap is detachably attached to the evaporated fuel discharge port of the evaporated fuel discharge pipe, even if the control valve does not operate due to an unexpected failure, the operator can remove the evaporated fuel cap and The evaporated fuel can be quickly released to the outside air via the evaporated fuel discharge pipe. Furthermore, since the internal pressure of the fuel tank can be brought close to the atmospheric pressure by opening the vaporized fuel discharge pipe, the fuel can be easily injected into the fuel tank. Further, even if the control valve fails, the fuel can be supplied to the fuel tank, and the restart of the internal combustion engine in an emergency can be ensured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structure of a first embodiment of an evaporated fuel discharge restraint device of the present invention.

FIG. 2 is a cross-sectional view showing the structure of a second embodiment of the evaporated fuel emission restraint device.

FIG. 3 is a cross-sectional view showing a conventional evaporated fuel emission restraining device.

[Explanation of symbols]

10 ... Fuel tank, 11 ... Fuel, 30 ... Filler pipe, 31 ... Fuel cap, 40 ... Evaporative fuel discharge pipe, 40
a ... evaporated fuel discharge port, 41 ... evaporated fuel cap, 60 ...
Canister, 70 ... Charge passage, 73 ... Control valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Hidano 1-4-1 Chuo, Wako City, Saitama Prefecture Honda R & D Co., Ltd.

Claims (1)

[Claims] 1. A canister that is connected to a charge passage connected to a fuel tank and adsorbs and releases evaporated fuel generated in the fuel tank; and a canister that is installed in the middle of the charge passage and is used for refueling the fuel tank. A control valve for opening a passage, and an evaporative emission control device for supplying the evaporated fuel to an engine through a purge passage connected to the canister, wherein the device is arranged in parallel with a filler pipe for supplying fuel to the fuel tank. An evaporative fuel discharge pipe connected to an upper portion of the fuel tank and connected to the outside air through an evaporative fuel discharge port; and an evaporative fuel cap that opens and closes the evaporative fuel discharge port. Deterrent device.